Fuel flow measuring system for an internal combustion engine powered vehicle

Abstract

A fuel flow measuring system includes a housing in which a pump is mounted. The housing is divided by a weir into two tank zones into one of which fuel returned by an engine fuel system is admitted and from the other of which fuel is drawn by the fuel system. The pump outlet is connected by a fuel flow measuring device to depth sensing means in said other tank zone to admit sufficient fuel to maintain the level in said other tank zone constant. Remaining fuel delivered by the pump is returned to a main storage tank via a pressure relief valve and a heat exchanger in series.

I claim: 
     
       1. A fuel flow measuring system comprising a housing in which there is mounted a constant flow electric fuel pump for drawing fuel from a main storage tank, a first tank zone in said housing to which excessive fuel delivered to the engine is returned in use, a second tank zone in said housing from which fuel is delivered to the engine, said second tank zone being vented to atmosphere, means sensitive to the depth of fuel in said second tank zone for admitting fuel from the outlet of the pump via a flow measuring device to said second tank zone so as to maintain the volume of fuel in said second tank zone constant, a pressure relief valve and a heat exchange device connected in series between the pump outlet and a return pipe for returning fuel to the main tank, and means for allowing fuel to pass from said first tank zone to said second zone of said housing. 
     
     
       2. A system as claimed in claim 1 in which said first and second tank zones are separated by a weir over which fuel can escape from the first tank zone to the second tank zone, said depth sensitive means acting to prevent fuel from the pump outlet being admitted to said second tank zone when the depth of fuel therein is greater than a predetermined maximum, which is lower than said weir. 
     
     
       3. A system as claimed in claim 2 in which said depth sensitive means comprises at least one float operated valve. 
     
     
       4. A system as claimed in any one preceding claim in which the exterior of the housing is provided with heat dissipating fins.